Overhead roll-up doors provide resistance to high winds and/or air pressure. These doors typically include a door panel having opposing side edges that engage with, and are vertically guided in, side columns. In order to enhance the door's resistance to high winds and/or air pressure, the opposing side edges of the door panel may include a thickened edge that engages the side columns when high winds “impact” the door panel. However, using a thickened edge may prevent the door panel and associated edges from disengaging from the side column if the door panel is impacted by an object or vehicle. This, in turn, often leads to damage to one or more of the side columns, door panel, door components, surrounding building structures, the vehicle, and/or any objects located near the door.
One method which has been used to facilitate disengagement of the door panel and thickened edges if the door panel is impacted by an object or vehicle is by making a portion of the side columns disengage-able. For example, U.S. Pat. No. 5,482,104 discloses a side column having a windbar(s) or strip(s) which engage a thickened edge when a wind load is applied to the door. If the door panel is impacted by an object or vehicle, the force imparted on the windbar(s) or strip(s) by the thickened edges will cause the windbar(s) or strip(s) to disengage from the side columns, allowing the door panel and edge to disengage. While such a configuration will allow the door panel to withstand a wind load and disengage if impacted, each time the door panel is disengaged because of an impact, the windbar(s) or strip(s) must be re-attached to the side columns.
Another method which is known in the prior art is to use a spring assembly to allow a portion of the side column to pivot out of the way when a force is applied to it by a thickened edge on a door curtain. For example, U.S. Pat. No. 6,942,003 discloses a side column having a windbar assembly which includes a tension spring capable of compressing when a thickened edge on the door panel applies a force to the windbar. The compression of the spring allows the thickened edge and door panel to escape the side columns. However, such a configuration does not provide for any enhanced wind resistance as the wind load increases, and indeed may allow the door panel to escape under substantial wind loads if the spring compresses. As is known in the art, springs may also break and wear out, lowering the wind locking capabilities of the side column and door panel.
Yet another method known in the prior art is to provide the thickened edge with a sloping face which engages a corresponding sloping surface on the side column and allow for the side column to deform if a force is applied on it by the door panel as a result of the door panel being impacted by a vehicle or object. However, such side columns do not provide any enhancement of the wind resistance of the door as the wind load is increased, inasmuch as the side columns are not designed to move in a manner which prevents the door panel from escaping the side columns.
Therefore, it would be advantageous to design a side column capable of bi-directional movement such that movement in the first direction will increase the wind load resistance of the door and door panel as a first force or the wind load increases while movement in the second direction will allow the door panel to more easily escape the side column if impacted by a vehicle or object.
It would be further advantageous to design a side column capable of providing a wind lock on a vertically moving door panel without utilizing thickened edges in order to allow for easier disengagement of the door panel if it is impacted.
The present invention is directed to solving these and other problems.